Die



Jan. 27, 1925.l

L. c. GERMAIN E1' AL 1'524'235 UWUHWM Patented Jan. 27, 1925.

UNITED STATES rareza PATENT oFFIcE.

LEON C. GERMAIN, OF CONWAY, AND ALBERTO G. GERMAIN AND CHARLES E. PAR- SONS, F GREENFIELD, MASSACHUSETTS.

DIE.

Application filed March 24, 1923. Serial No. 627,433.

To all whom t may concern:

Be it known that we, LEON C. GERMAIN, ALDEnro G. GERMAIN, and CHARLES E. PAR- soNs, citizens of the United States, residing at Conway, Greenfield, and Greenfield, respectively, in the county of Franklin and State of Massachusetts, have invented certain new and useful Improvements in Dies, of which the following is a specification.

This invention relates to dies for cutting screw-threads, and methods of making the same.

An object of the invention is the provision of a die in which the cutting threads are arranged at an angle to the axis of the die,

whereby a shearing cut is obtained.

A further object is the provision of a die having inclined clearance holes relieved at each side to feed the cut material from the die.

A further object is the provision of a die which may be reversed and operated with either face toward the work.

In constructing the die, the clearance holes are first drilled in a blank of metal at equal distances from the center. The center hole is then drilled and tapped out, and the threads cut therein. The clearance holes are finished to provide a relief, consisting of a relatively flat surface adjacent the cutting threads, which feeds the cut metal out wardly and prevents clogging of the die.

In the accompanying drawings, we have shown several embodiments of the invention. In this showing:

Figure 1 is a plan view of one form,

Figure 2 is a transverse sectional view on line 2-2 of Figure 1,

Figure 3 is a side elevation showing the die in use,

Figure 4f is a plan view of another form of the invention,

Figure 5 is a transverse sectional view on line 5-5 of Figure 4,

Figure 6 is a side elevation showing the die in use,

Figure 7 is a plan view of a two-piece die, and,

Figure 8 is a side elevation of the same.

Referring to Figures 1 to 3 of the drawings, the die consists o-f a blank 1, which may be circular as shown, or may be formed in any desired shape. In this instance, we have shown a onefpiece die, but it will be apparent that the invention applies, to twopiece dies as well. In forming the die, a plurality of clearance holes 2 are drilled in the stock at equal distances from the center and equally spaced from each other. As shown, these clearance holes are arranged at an angle to the axis of the die. A center hole 3 is then cut in the blank and threads 4.- tapped on the surface of this hole. The threads are finished by cutting back the upper edge at a point where the work is iirst engaged, as indicated at 5, and cutting back t-he lower edge at a point at the opposite side, as indicated at 6, to provide a cutting point which first engages the work. Referring to Figure 2 of the drawings, it will be noted that the edge 7 o-f the threads is at an incline, caused by the intersection of the center hole 3, and the clearance holes 2. This causes the lower thread to engage first in cutting and the remaining threads to engage in turn. This provides a shearing cut, as distinguished from the present type of cut where all of the threads of a die engage at the same time. If the die is turned over, it will be apparent that the working edge of the threads will be reversed and the proper clearance will also be obtained, providing a cutting point at the bottom where the tool .[irst engages and a recess at the top.

After the threads have been cut, the clear ance holes are then relieved by slightly flattening the side walls, as at 8, adjacent the point where the clearance hole intersects the center hole. The advantage of this relief will be apparent from an inspection of Figure 3 of the dra-wings. In this figure, we have shown a bolt 9 having threads 10 cut thereon. By providing the inclined clearance holes with substantially fiat surfaces adjacent the point where the metal is being cut, the metal is fed outwardly, as indicated at 11. This prevents the accumulation of short pieces of meta-l or chips in the clearance holes, which tend to strip the threads when the die is removed.

In Figures 4: to G of the drawings, we have shown a die 12 substantially the same as that shown in Figures 1 to In this instance, howevcr, the clearance holes 13 are inclined in the opposite direction. As shown in Figure 6 of the drawings, this causes the cut pieces of metal 14: to be projected in the opposite direction toward the work 15.

In Figures 7 and 8 of the drawings, we have shown a die formed of a rectangular -into two sections.

-Dies heretofore used have been referred to as self-clearing dies, lont as a inatter ot ifaetythe ont inetal passes into the clearance the Wallso` the clearance holes and is broken `oil' into relatively short pieces.

Minass, which ills the clearance holes. 20 1 Q these chips frequently l'all vinto the ont.

Yfliorin'ed thread is destroyed.

the inclined clearance holes and cuttingthe holes at sach an angle that it strikes against As the die is oiled, these short Vpieces l'orin, a seggi renioa'ing the die' troni the world soine of threads and as thedie passes over rhein1 the By pro'v'idinpT threads with a shearing ent, the strips forinedfby theciitting operation reseinble the cnt nietal delivered li'oin a lathe ni cnt* ."tingthreads by `lathe tools and these Ystrips passinto'the clearance holes at such an angle tliat'they are readily delivered in av direction parallel to the axis of'thedie.' This eliminates the possibility ol' the Vpieces ol cnt InV nietal breaking` oil" and filling the elearanee holes.

lt is to be iniderstood that the forms oi' the inventionheieivith `shown and described are to he taken as preferred examples of the saine, and that vai-ions changes in the shape. size, and arrangement of parts may be resorted to without departing `lroin the spirit or' the invention or the scope of the snh joined claim. i

Having' thus described onil invention, we claini:

A die provided with ay central opening and a plurality of clearance openings inter seetingvlv` therewitl. and having then.' axes disposed at an inclination to that of said een* tral opening. whereby a plurality of substantially spirally `disposed landsare provided. and threads .pii'ivided on said lands` the threads adjacent one face of the die heini; relieved on one side of the land and the threads adjacent the other laee of the die being relieved on the opposite side of the land. whereby each land has cutting edges on one side at one end and on the other side at the opposite end.

ln testimony whereof, we aliix onr signin tures.

LEON C. GERMAIN. ALDERIC G. GERMAIN. CHARLES E. PARSONS. 

